Callithrix geoffroyiGeoffroy's marmoset

Geographic Range

Geoffroy's marmosets (Callithrix geoffroyi) are found in southeastern Brazil. They inhabit the state of Espirito Santo and the forested eastern and north-eastern part of the state of Minas Gerais. They are found as far north as the Rio Jequitinhonha and Aracuai and south to near the state border of Espirito and Rio de Janeiro. The population south of Rio Jequitinhonha originated from animals released near the river's mouth in 1975. This population has since spread eastward. A hybrid population of Callithrix penicillata x C. geoffroyi has been found in the Serra da Piedade along the Rio Piracicaba. (Rylands and Mendes, 2008)


Geoffroy's marmosets inhabit secondary lowlands and sub-montane forest, evergreen, and semideciduous forest, forest edge and dry forest patches. They are generally found at an elevation of between 500 and 700 m, but can be found as high as 800 m. (Rowe, 1996; Rylands and Mendes, 2008)

  • Range elevation
    500 to 800 m
    1640.42 to 2624.67 ft
  • Average elevation
    600 m
    1968.50 ft

Physical Description

Geoffroy's marmosets are small primates, only about 200 mm in length, with a tail of about 290 mm. Females tend to weigh around 190 g, while males range from 230 g to 350 g. The body is predominately dark or blackish brown. The tail is ringed with gray and black bands. Adults have white foreheads, cheeks, temples and throats. Adults also have tufts of black fur in front of their ears. Juveniles differ from adults in that they lack both the ear tufts and white markings around the face. Juveniles begin to grow their ear tufts at an age of about 2 weeks, and have full adult markings by the age of 5 months. (Rowe, 1996; Stevenson and Rylands, 1988)

  • Sexual Dimorphism
  • male larger
  • Range mass
    190 to 350 g
    6.70 to 12.33 oz
  • Average length
    198 mm
    7.80 in


The dominant male and female in each group of Geoffroy's marmosets form a monogamous pair bond. Only this pair will breed. Dominant behavior of the breeding female will halt ovulation in other females in the group. This process may be aided by pheromones produced in the scent glands of the dominant female. As a result, subordinate females cannot reproduce while they remain with the group. Such hierarchy is less evident among males. Usually only one male mates with the breeding female, but polyandry (usually rare among mammals) has been observed under certain circumstances. (Wakenshaw, 1999)

Pre-copulatory courtship usually begins with sniffing each other's muzzles and genitalia, as well as marking objects, licking, grooming and huddling. These behaviors are also seen in post-copulatory courtship. These behaviors increase as the female reaches estrus. (Wakenshaw, 1999)

Female estrus cycles vary from 14 to 21 days. Should a female become pregnant, the gestation lasts about 140 to 148 days. Parturition may take up to an hour. Usually twins are born, but sometimes singletons or triplets occur. The male will assist with the birth by licking the babies before giving them to the mother. Other family members may help to eat the placenta. Post-partum estrus occurs 2 to 14 days after giving birth. Young are weaned by 5 or 6 months and reach sexual maturity between 15 and 18 months. (Wakenshaw, 1999)

  • Breeding interval
    There are usually 150 to 152 days between births in Geoffroy's marmosets.
  • Breeding season
    Geoffroy's marmosets breed year round.
  • Range number of offspring
    1 to 3
  • Range gestation period
    140 to 148 days
  • Range weaning age
    5 to 6 months
  • Range age at sexual or reproductive maturity (female)
    15 to 18 months
  • Range age at sexual or reproductive maturity (male)
    15 to 18 months

A female Geoffroy's marmoset will suckle both of her twins at the same time, until the young are weaned. For the first week after young are born, the father carries the babies exclusively. After this, the male will still be the primary carrier, but all members of the family participate in carrying the young. Older siblings assist in the rearing of the younger siblings, by which they learn skills essential to raising their own young in the future. Females primarily provide milk for their young. (Wakenshaw, 1999)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • male
      • female
  • pre-independence
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • post-independence association with parents
  • extended period of juvenile learning


Geoffroy's marmosets generally live about 10 years. (Richardson, 2007)

  • Typical lifespan
    Status: wild
    10 (high) years


Geoffroy's marmosets are diurnal, arboreal, and scansorial. They live in family groups of between 8 and 10 individuals. During the wet season, Geoffroy's marmosets spend 32.1% of their time resting, 21% feeding, 20% moving, 14% foraging, 13% gouging (for gum), and 3% doing other activities such as playing, grooming, scent marking and vocalizing. During the dry season, time spent resting drops to 17.8% and time spent foraging increases to 20.6%. Geoffroy's marmosets are reported to follow swarms of army ants in order to catch the insects flushed out by the ants. (Rowe, 1996)

  • Range territory size
    .1 to .4 km^2

Home Range

Groups defend a home range of between 10 ha and 40 ha. (Rylands and Mendes, 2008)

Communication and Perception

Geoffroy's marmosets make alarm calls when they perceive a threat. They have also been observed scent marking. Allogrooming has been observed too, and is thought to contribute to calming the group down after a threat has passed. (Caine, 1998; Passamani, 1998)

Food Habits

Geoffroy's marmosets are omnivorous, eating mostly fruit, insects, and plant gums. They also eat flowers, nectar, frogs, snails, lizards, and spiders. These small primates are able to gouge into tree trunks, branches, and vines to obtain gum. (Passamani, 1998; Rowe, 1996; Rylands and Mendes, 2008)

  • Animal Foods
  • amphibians
  • reptiles
  • insects
  • terrestrial non-insect arthropods
  • mollusks
  • Plant Foods
  • fruit
  • nectar
  • flowers
  • sap or other plant fluids


Members of the Family Callitrichinae, including Geoffroy's marmosets, are highly affected by predation, perhaps to the highest degree of any primate. Field reports indicate that monitoring for predators is a high priority in the lives of marmosets. Groups of C. geoffroyi respond to predator threats by increasing rates of vigilance and decreasing rates of play and foraging. Members of groups share the task of monitoring by rotating occupation of the best look-out point. Geoffroy's marmosets have a variety of responses to raptors, snakes, and felids as well as other predators. Wild Geoffroy's marmosets react to predators with combinations of monitoring, alarm calls, mobbing, fleeing, and freezing. (Caine, 1998)

Ecosystem Roles

Geoffroy's marmosets prey on a variety of small vertebrates and invertebrates and provide prey for larger predators. (Passamani, 1998; Rowe, 1996; Rylands and Mendes, 2008)

Economic Importance for Humans: Positive

Geoffroy's marmosets are occasionally captured for the pet industry. (Rylands and Mendes, 2008)

Economic Importance for Humans: Negative

There are no known adverse effects of Geoffroy's marmosets on humans.

Conservation Status

Geoffroy's marmosets are considered "Least Concern" by the International Union for Conservation of Nature. The population trend for this species is classified as stable. However, widespread destruction is causing their populations to decline. The range of C. geoffroyi was once throughout the Brazilian Atlantic forest, but only about 1% to 5% of this habitat remains. For example, less than 6.8% of the Atlantic forest remains in the state of Minas Gerais. However, C. geoffroyi is considered relatively abundant and inhabits many protected areas. For this reason, their rate of population decline does not warrant a threatened listing. In 1982, Russell Mittermeier recommended that C. geoffroyi be listed as endangered, but studies conducted in 1991 found them to be locally abundant, if patchily distributed. In 1994, 1996, and 2000 C. geoffroyi was listed as vulnerable by the IUCN. Today, it is not considered under serious threat. (Passamani, 1998; Rylands and Mendes, 2008)

Other Comments

Callithrix geoffroyi was declared a separate species in 1988. It was previously considered to be a subspecies of Callithrix jacchus. (Rowe, 1996)


Brittany Murphy (author), Michigan State University, Barbara Lundrigan (editor, instructor), Michigan State University, Tanya Dewey (editor), Animal Diversity Web.



living in the southern part of the New World. In other words, Central and South America.

World Map


uses sound to communicate


young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.


Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


uses smells or other chemicals to communicate

cooperative breeder

helpers provide assistance in raising young that are not their own


animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.


offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).


Having one mate at a time.


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.


an animal that mainly eats all kinds of things, including plants and animals

pet trade

the business of buying and selling animals for people to keep in their homes as pets.


Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).


rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them


reproduction that includes combining the genetic contribution of two individuals, a male and a female


associates with others of its species; forms social groups.


uses touch to communicate


Living on the ground.


defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.


uses sight to communicate


reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year


Caine, N. 1998. Cutting Costs in Response to Predatory Threats by Geoffory's Marmosets (Callithrix geoffroyi). American Journal of Primatology, Vol. 46: 187-196.

Hearn, J. 1978. The Endocrinology of Reproduction in the Common Marmoset, Callithrix jacchus . Pp. 163-171 in D Kleiman, ed. The Biology and Conservation of the Callitrichidae. Washington, D.C.: Smithsonian Institution Press.

Passamani, M. 1998. Activity Budget of Geoffroy's Marmoset (Callithrix geoffroyi) in an Atlantic Forest in Southeastern Brazil. American Journal of Primatology, 46: 333-340.

Richardson, M. 2007. "Geoffroy's marmoset (Callithrix geoffroyi)" (On-line). ARKive. Accessed April 06, 2009 at

Rowe, N. 1996. The Pictoral Guide to Living Primates. East Hampton, New York: Pogonias Press.

Rylands, A., S. Mendes. 2008. "2008 IUCN Red List of Threatened Species" (On-line). Callithrix geoffroyi. Accessed March 24, 2009 at www.iucnredlist.ort.

Stevenson, M., A. Rylands. 1988. The Marmosets, Genus Callithrix . Pp. 131-222 in R Mittermeier, A Rylands, A Coimbra-Filho, eds. Ecology and Behavior of Neotropical Primates, Vol. 2. Washington, D.C.: World Wildlife Fund.

Wakenshaw, V. 1999. The Management and Husbandry of Geoffroy's Marmoset. International Zoo News, 46: 1. Accessed April 04, 2009 at